fix: rename llama_stack_api dir (#4155)

# What does this PR do?

the directory structure was src/llama-stack-api/llama_stack_api

instead it should just be src/llama_stack_api to match the other
packages.

update the structure and pyproject/linting config

---------

Signed-off-by: Charlie Doern <cdoern@redhat.com>
Co-authored-by: Ashwin Bharambe <ashwin.bharambe@gmail.com>

src/llama_stack_api/README.md

@@ -0,0 +1,103 @@
+# llama-stack-api
+
+API and Provider specifications for Llama Stack - a lightweight package with protocol definitions and provider specs.
+
+## Overview
+
+`llama-stack-api` is a minimal dependency package that contains:
+
+- **API Protocol Definitions**: Type-safe protocol definitions for all Llama Stack APIs (inference, agents, safety, etc.)
+- **Provider Specifications**: Provider spec definitions for building custom providers
+- **Data Types**: Shared data types and models used across the Llama Stack ecosystem
+- **Type Utilities**: Strong typing utilities and schema validation
+
+## What This Package Does NOT Include
+
+- Server implementation (see `llama-stack` package)
+- Provider implementations (see `llama-stack` package)
+- CLI tools (see `llama-stack` package)
+- Runtime orchestration (see `llama-stack` package)
+
+## Use Cases
+
+This package is designed for:
+
+1. **Third-party Provider Developers**: Build custom providers without depending on the full Llama Stack server
+2. **Client Library Authors**: Use type definitions without server dependencies
+3. **Documentation Generation**: Generate API docs from protocol definitions
+4. **Type Checking**: Validate implementations against the official specs
+
+## Installation
+
+```bash
+pip install llama-stack-api
+```
+
+Or with uv:
+
+```bash
+uv pip install llama-stack-api
+```
+
+## Dependencies
+
+Minimal dependencies:
+- `pydantic>=2.11.9` - For data validation and serialization
+- `jsonschema` - For JSON schema utilities
+
+## Versioning
+
+This package follows semantic versioning independently from the main `llama-stack` package:
+
+- **Patch versions** (0.1.x): Documentation, internal improvements
+- **Minor versions** (0.x.0): New APIs, backward-compatible changes
+- **Major versions** (x.0.0): Breaking changes to existing APIs
+
+Current version: **0.4.0.dev0**
+
+## Usage Example
+
+```python
+from llama_stack_api.inference import Inference, ChatCompletionRequest
+from llama_stack_api.providers.datatypes import ProviderSpec, InlineProviderSpec
+from llama_stack_api.datatypes import Api
+
+
+# Use protocol definitions for type checking
+class MyInferenceProvider(Inference):
+    async def chat_completion(self, request: ChatCompletionRequest):
+        # Your implementation
+        pass
+
+
+# Define provider specifications
+my_provider_spec = InlineProviderSpec(
+    api=Api.inference,
+    provider_type="inline::my-provider",
+    pip_packages=["my-dependencies"],
+    module="my_package.providers.inference",
+    config_class="my_package.providers.inference.MyConfig",
+)
+```
+
+## Relationship to llama-stack
+
+The main `llama-stack` package depends on `llama-stack-api` and provides:
+- Full server implementation
+- Built-in provider implementations
+- CLI tools for running and managing stacks
+- Runtime provider resolution and orchestration
+
+## Contributing
+
+See the main [Llama Stack repository](https://github.com/llamastack/llama-stack) for contribution guidelines.
+
+## License
+
+MIT License - see LICENSE file for details.
+
+## Links
+
+- [Main Llama Stack Repository](https://github.com/llamastack/llama-stack)
+- [Documentation](https://llamastack.ai/)
+- [Client Library](https://pypi.org/project/llama-stack-client/)